Wind, solar and less demand for power cutting CO2 emissions

These are solar panels at the Alamo 6 Solar Farm in Pecos County, Texas built by San Antonio-based OCI Solar Power.

These are solar panels at the Alamo 6 Solar Farm in Pecos County, Texas built by San Antonio-based OCI Solar Power.

Photo: John Davenport, STAFF / San Antonio Express-News

Photo: John Davenport, STAFF / San Antonio Express-News

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These are solar panels at the Alamo 6 Solar Farm in Pecos County, Texas built by San Antonio-based OCI Solar Power.

These are solar panels at the Alamo 6 Solar Farm in Pecos County, Texas built by San Antonio-based OCI Solar Power.

Photo: John Davenport, STAFF / San Antonio Express-News

Wind, solar and less demand for power cutting CO2 emissions

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Carbon dioxide emissions are dropping nationwide, reflecting a decline in electricity consumption and an increase in the use of cleaner energy sources to produce power.

The Energy Department reported that power generators cut their emissions of carbon dioxide, a greenhouse gas that traps heat in the atmosphere and increases worldwide temperatures, by 28 percent over in the past 13 years. Carbon dioxide emissions from the power sector, which totaled 1,744 million metric tons last year, are the lowest they’ve been since 1987.

The reduction in overall demand for electricity had the single biggest impact on lowering carbon emissions. The decrease likely sliced 654 million metric tons of greenhouse gases from the atmosphere between 2005 and 2017, the government reported. Switching from coal to natural gas was responsible for cutting another 329 million metric tons of CO2 emissions. Adding more renewable sources of power cut another 316 million metric tons.

Demand for electricity has fallen in six of the past 10 years, due to declining consumption among industrial users. Residential and commercial demand has remained relatively flat. In the decade before 2005, demand for electricity was rising about 2 percent a year.

At the same time, the power sector has become less reliant on coal-fired and petroleum-fired fuel sources. Some of the shift has been driven by market forces, reflecting ample supplies and lower prices for natural gas along with the ability of producers to add new natural gas-fired capacity when it’s needed.

Renewable sources of power such as wind and solar have also grown, driven by state policies and federal tax incentives to develop the low-cost power sources. Last year, total annual generation from wind and solar sources reached 8 percent in the U.S.

In Iowa, 37 percent of the state’s power came from wind and solar, and in Kansas, those two renewable sources represented 36 percent of the state’s power supply. In all, 10 states get at least 20 percent of their power from wind and solar.

In Texas, 18 percent of electricity came from wind and solar last year. Texas leads the nations in wind generation capacity, with well over 20,000 megawatts — enough to power more than 4.3 million homes on a hot summer day. Wind energy in Texas produces more electricity than the combined output of the state’s two nuclear power plant.

Power producers are also relying more on natural gas-fired generators as low prices have made the fuel competitive with coal.

Average annual capacity for the natural gas-fired generators at PJM Interconnection, the grid operator that regulates power supplies to 13 states in the Midwest and Mid-Atlantic region, has been on the rise in recent years, reflecting the shift toward natural gas. The increase has been the largest of any regional grid operator over the past five years, according to the Energy Department. Capacity factors indicate how often a generator runs.

Three years ago, PJM, the nation’s largest competitive wholesale electricity market, generated more power using natural gas than it did using coal-fired sources.